docs: def accpro20_summary(self, cutoff):
          """Parse the ACCpro output file and return a summary of percent exposed/buried residues based on a cutoff.
  
          Below the cutoff = buried
          Equal to or greater than cutoff = exposed
          The default cutoff used in accpro is 25%.
  
          The output file is just a FASTA formatted file, so you can get residue level
              information by parsing it like a normal sequence file.
  
          Args:
              cutoff (float): Cutoff for defining a buried or exposed residue.
  
          Returns:
              dict: Percentage of buried and exposed residues
  
          """
          summary = {}
  
          if cutoff < 1:
              cutoff = 1 * 100
  
          records = read_accpro20(self.out_accpro20)
  
          for k,v in records.items():
              seq_summary = {}
  
              exposed = 0
              buried = 0
              for s in v:
                  if s > cutoff:
                      exposed += 1
                  else:
                      buried += 1
  
              seq_summary['percent_exposed-accpro20'] = exposed / float(len(v))
              seq_summary['percent_buried-accpro20'] = buried / float(len(v))
  
              summary[k] = seq_summary
  
          return summary